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tresstylez
tresstylez

Reputation: 1839

Which PHP data structure for quick single VALUE lookups with unique KEY?

I have a dynamically generated list of URL's from our internal network. For each URL, I want to:

  1. Find the IP of the URL.
  2. Compare the IP to a list of IP's and their associated server.
  3. Return the server associated with the IP.

The IP of course is UNIQUE in the list of IP's, so is there a recommended way to initially store the list of IP values so I can supply it with a an IP (key) and get back the associated server (value)?

I've looked at multidimensional arrays, or even brute force -- just create an array for each individual server's IP list -- but that seems inefficient.

Here is the PHP I want to have (psuedo):

$IPServerList = array(0 => array(ip=>1.2.3.4,server=>"server1"),
       1 => array(ip=>2.1.3.4,server=>"server2"),
       2 => array(ip=>3.1.3.3,server=>"server1"));

getServer("url1.mycoolurl.com");

function getServer($url) {
    $ip = gethostbyname($url);
"Search $IPServerList for this $ip and return the 'server' value"
    // 

}

Are there any specific ways I should be storing the IP/Server list? Any recommended built in PHP functions to do the search? Any help is appreciated!

Upvotes: 0

Views: 591

Answers (5)

user229044
user229044

Reputation: 239462

I'm not seeing any obvious reason for avoiding associative arrays:

$IPServerList = array(
  '1.2.3.4' => "server1",
  '2.1.3.4' => "server2",
  '3.1.3.3' => "server1",
);

Arrays in PHP double has hashs/maps/dictionaries, depending on what you're used to calling them. The point is, you can use any unique string/number for your array index, and since you seem to have a 1-to-1 mapping of IPs to server names, this seems ideal.

I don't think you're likely going to find a faster way in PHP to access your data, and you can't beat it for simplicity:

 if (array_key_exists($IPServerList, '192.168.1.1')) {
   echo $IPServerList['192.168.1.1'];
 }

The PHP manual on arrays will be useful.

Upvotes: 3

Dutchie432
Dutchie432

Reputation: 29170

This is the best scheme I can think of is something like this. 

$servers= array(
    'xxx.xxx.xxx.001' => array(
        'name' => "server1", 
        'os' => "Windows"
        ),
    'xxx.xxx.xxx.002' => array(
        'name' => "server2", 
        'os' => "Linux"
        ),
    'xxx.xxx.xxx.003' => array(
        'name' => "server3", 
        'os' => "Mac"
        )
);

Doing something like this allows you to store more information about server other than its name, as well as access settings using the IP address without looping.

$ip = 'xxx.xxx.xxx.002';
if ($servers[$ip]){
    $serverName = $servers[$ip]['name'];
    $serverOs = $servers[$ip]['os'];
}

Upvotes: 1

Christa
Christa

Reputation: 485

If you use arrays to store the data, as in your example you could use in_array to check if it is there.

http://php.net/manual/en/function.in-array.php

You might also check out array_search() and array_key_exists()

Upvotes: 0

Marc B
Marc B

Reputation: 360782

How about just keying the array off the ips?

$IPServerList = array(
    '1.2.3.4' => 'server1',
    '2.3.4.5' => 'server2',
    '3.4.5.6' => 'server3'
);

PHP's arrays are a mishmash of both array and hashes, and support using both types of keys simultaneously, so there's no reason to generate a unique numeric key when the IP would serve as well:

echo $IPServerList['1.2.3.4']; // produces 'server1'

And if you needed to store more than just the name, you can nest the arrays:

$IPServerList['1.2.3.4'] = array('name' => 'server1', 'this' => 'x', 'that' => 'y')

Upvotes: 0

powtac
powtac

Reputation: 41070

// IP to search
$ip = '127.0.0.1';

foreach ($IPServerList as $entry) {
    if ($entry['ip'] == $ip) {
        echo 'MATCH :) ';
        var_dump($entry);
        break;
    }
}

Upvotes: 0

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